Foster + Freeman’s Natural 1 IR Fluorescent Fingerprint Powder
Written by Michael E. Stapleton, M.A. & Kourosh Nikoui, CLPE   
Many in the field of forensics today are seeing the value of utilizing infrared (IR) imaging to visualize various forms of hidden evidence such as bloodstains and gunshot residue on dark fabrics. They have discovered that digital cameras can be converted to capture only IR images by the removal of an IR-blocking filter installed by the camera manufacturer in front of the camera’s sensor. After this conversion, they are able to visualize evidence previously obscured.
 
Now, a new IR latent print development powder has been introduced by Foster + Freeman for visualizing latent prints on “difficult” multicolored substrates. The powder is called “Natural 1 IR Fluorescent Fingerprint Powder”. This new latent print powder fluoresces within the near IR spectrum of light.
 
The Natural 1 IR Fluorescent Fingerprint Powder is a blue-green colored powder that is made from algae. The powder is non-toxic and safe to handle. The powder was designed under the scientific premise that plants absorb visible light and reflect back IR light that cannot be absorbed. The latent prints visualized with this powder will tend to photograph white or slightly gray in color and the substrate or background will tend to darken. The powder is applied to the surface of interest by either a latent print fiberglass brush or feather duster.
 
Fluorescence with this powder is achieved by using either a blue forensic light source operating in the 420-470nm range, or a red forensic light source operating in the 600-650nm range. The results are viewed and photographed through the “live view” function of a digital camera that has been converted to IR. Also, a DSLR camera converted to full spectrum could be used, but will require extremely dark IR Schott glass filters designed to pass through only infrared light.
 
The equipment used with the Natural 1 powder for the purposes of this article and the incorporated images were:
 
  • Nikon D810 DSLR that had been converted to full spectrum capabilities
  • Nikon Nikkor 60mm and 105mm f/2.8 Micro lens
  • Infrared Schott Glass Filters - 693nm and 751nm
  • Nikon D70 DSLR that had been converted to IR only with an internal 720nm cutoff filter
  • Foster + Freeman Crime-lites 82S handheld red (600-650nm) and blue (420-470nm) forensic lights
  • A cyan forensic light source operating at 505nm
Substrates used for this article were:
  • Portions of currencies with complicated backgrounds
  • CDs
  • FedEx mailing envelopes (Tyvek type)
The exemplar photographs were taken in camera RAW file format and aperture priority with the lens aperture set to f/8. The authors achieved the best results by using the blue forensic light source. Relatively fresh latent impressions were used for the purpose of this product review. The sensitivity of this powder for visualization of older impressions was not determined during this evaluation.
 
The minimum recommended and most economical equipment to use with the Natural 1 latent print powder would be the following:
  • DSLR camera converted to IR only (optimal if the camera has the “live view” function)
  • Macro lens - 50 or 60mm to 105mm
  • Blue forensic light source operating within the 420-470nm range
  • Feather-duster latent print applicator
  • Foster + Freeman’s Natural 1 IR Fluorescent Fingerprint Powder
The use of this IR powder should be considered if the department has the capability for infrared latent print photography or is contemplating purchasing the necessary equipment. Its use is especially suited to substrates that have a multi-colored background or in situations where fluorescent development procedures would interfere with the visualization of the latent print. It should be noted that the Natural 1 powder is difficult to see while processing to locate latent prints. Its use for general searching at a crime scene would be very challenging, especially using a camera without “live view”. It is best used as Foster + Freeman intended—that is, on difficult patterned and other multicolored substrates.
 

Foreign currency exemplar as it appeared after being develoepd using hte Natural 1 IR Fluorescent Fingerprint Powder (top image) and the same piece of currency after being inverted using photo-editing software (above).
 

The image on the left is as the currency appeared originally, after being treated with the fingerprint powder. The image on the right was inverted in photo-editing software. Photos courtesy Dr. Roberto King.


The typical "rainbow" effect on a CD was eliminated.
 

Images of latent prints on a FedEx Tyvek mailing envelope.

About the Authors
 
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it retired after 34 years as a Special Agent with the Federal Bureau of Investigation. For nearly four decades he has conducted fingerprint identification courses. Upon retirement from the Bureau he formed Stapleton & Associates, LLC, a forensics training and consulting company. He and his associates conduct friction ridge identification courses, latent print development courses, and other advanced forensic training courses throughout the U.S. and abroad. Information about his upcoming courses can be found on these two websites: StapletonAndAssociates.com and forensicsRus.com
 
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it is a retired Chief Forensic Specialist. He is currently the owner and manager of Nikoui & Associates, Forensic Identification Services & Consulting, LLC, that provides a variety of latent print services and training to local law enforcement agencies in northern California. He is certified by the IAI as a Latent Print Examiner, Senior Crime Scene Analyst, and Forensic Photographer. He has over 30 years of experience in the field.
 
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